EP0531492B1 - Ionically conducting polymer materials - Google Patents

Abstract

PCT No. PCT/FR92/00198 Sec. 371 Date Nov. 6, 1992 Sec. 102(e) Date Nov. 6, 1992 PCT Filed Mar. 4, 1992 PCT Pub. No. WO92/16028 PCT Pub. Date Sep. 17, 1992.The present invention relates to ionically conductive polymeric materials, to their preparation and to their use as a solid electrolyte. The materials comprise a solid solution of one or more salts in a polymer and are characterized in that the transport and the mobility of a metal cation Mn+ which has the valency n, 1</=n</=5, are provided by at least one complex anion, corresponding to the general formula [MZnYp]p- formed between an anionic ligand Z-, an anionic ligand Y- and the cation Mn+, with 1</=p</=3. Application to the formation of electrochemical generators and of electrochemical systems which make it possible to affect the transmission of light.

Description

The present invention relates to ionically conductive polymeric materials, their preparation and their use as a solid electrolyte.

The metal salts MX _n in which M represents a metal cation and X represents a monovalent anion, form complexes with certain solvating polymers, in particular those incorporating polyether type sequences (for example poly (ethylene oxide) PEO, poly ( propylene oxide) PPO, poly (bis ω-methoxy-oligooxyethylene-phosphazene) ME _n P) or polyamines (PEI). These materials have, in a determined temperature and salt concentration range, an ionic conduction which can be used for the production of electrochemical systems, in particular accumulators (European Patent N ° 13199).

The ionic conductivity of these complexes depends on the degree of dissociation of the salt MX _n and the highest values for a given species M are obtained with anions X⁻ for which the negative charge is delocalized and which have no complexing character. However, the mobility of the M ^{n +} cations in this macromolecular medium depends on the rate of exchange of the ligands incorporated into the macromolecular frame, in the form of solvation units, around these cations. For n> 1 and / or for the transition elements, these kinetics are slow and generally result in low or zero values of the number of cation transport in these materials. In particular, it is therefore difficult to carry out electrochemical reactions involving a reversible contribution to the electrode of the species M ^{n +} (metal deposition-dissolution, insertion, etc.).

The present invention aims to remedy these drawbacks by providing materials of the polymer-salt type in which the transport of the species M is independent of the dissociation of the salt MX _n into anions and cations M ^{n +} .

The ionically conductive materials of the present invention, comprising a solid solution of one or more salts in a polymer, are characterized in that the transport and the mobility of a metal cation M ^{n +} having the valence n, 1 ≦ n ≦ 5, are provided by at least one complex anion, corresponding to the general formula [MZ _n Y _p ] ^p- formed between an anionic ligand Z⁻, an anionic ligand Y⁻ and the cation M ^{n +} , with 1 ≦ p ≦ 3.

dans laquelle

• A est un cation de valence p susceptible d'être facilement solvaté par le polymère, avec p=1, 2 ou 3
• (u.s.) désigne l'unité de solvatation du polymère
• u représente le nombre d'unités de solvatation portées par la trame polymère assurant la solvatation d'un cation A.
• x, y et z sont tels que la relation z + y - nx = p soit satisfaite et qu'ils permettent la coexistence en quantités finies, de l'anion complexe [MZ_nY_p]^p- et d'une espèce choisie dans le groupe constitué par l'anion Z⁻, l'anion Y⁻, l'anion complexe [MZ_nY_p+1]^(p+1)- et l'espèce neutre MZ_n.

Among the ionically conductive materials of the present invention, mention may be made of the polymer complexes represented by the overall formula $${\text{Poly (us)}}_{\text{u}}{\text{A (M}}_{\text{x}}{\text{Z}}_{\text{z}}{\text{Y}}_{\text{y}}\text{)}$$

in which

• A is a cation of valence p capable of being easily solvated by the polymer, with p = 1, 2 or 3
• (us) denotes the unit of solvation of the polymer
• u represents the number of solvation units carried by the polymer frame ensuring the solvation of a cation A.
• x, y and z are such that the relation z + y - nx = p is satisfied and that they allow the coexistence in finite quantities, of the complex anion [MZ _n Y _p ] ^p- and of a species chosen in the group consisting of the anion Z⁻, the anion Y⁻, the complex anion [MZ _n Y _{p + 1} ] ^{(p + 1) -} and the neutral species MZ _n .

The transport of the species M ^{n +} is therefore ensured by diffusion of the anionic complex [MZ _n Y _p ] ^p- to the electrode. At the electrode, the complex loses metal M which is deposited on the electrode. In parallel, the complex anion is reformed from MZ _n or its charge is increased, or else the ligand Y⁻ and / or the ligand Z⁻ are released by desolvation of the complex anions. The complex anion having an increased charge or Y⁻ or Z⁻ migrate to the opposite electrode. The phenomenon is reversed if the direction of the current is reversed.

The relatively high mobility of the anionic species in the solvating polymers makes it possible to ensure rapid kinetics for the above-mentioned mechanism.

The cation A capable of being easily solvated by the polymer can be chosen from alkali metals, alkaline earth metals, lanthanum, quaternary ammonium radicals, amidinium radicals, guanidinium radicals. Among the quaternary ammonium groups, mention may be made of those which correspond to the formula NH _(4-j) R _j ⁺. Among the amidinium groups, mention may be made of those which correspond to the formula RC (NH _2-j R _j ) ₂⁺. Among the guanidinium groups, there may be mentioned those which correspond to the formula C (NH _2-j R _j ) ₃⁺. In all cases, R can be hydrogen, an alkyl, oxaalkyl or aryl group, and j can take the integer values 0,1 or 2.
The preferred cations A of the invention are those which, because of their high ionic radius, ensure the best ionic dissociation of the complexes and for which the ligand Z⁻ has no complexing power. In this regard, the K⁺, Cs⁺, Sr⁺, Ba⁺⁺ and NH₄⁺ ions are particularly preferred.

M can be chosen from metals whose valence n is from 1 to 5. As examples, there may be mentioned alkali metals and alkaline earth metals having an ionic radius sufficiently small to be able to be easily complexed, transition metals and rare earth. Particularly preferred are Li, Mg, Ca, Sr, Mn, Fe, Ni, Co, Cu (I, II) Ag, Zn, Cd, Al, Sn (II, IV), Bi, Hg, Pb, Y, La .

Z⁻ and Y⁻, identical or different, can be chosen from:
= halogens such as F⁻, Cl⁻, Br⁻, I⁻;
= pseudohalogens corresponding to the formula QS⁻;
= the radicals R _F CO₂⁻, (R _F CO) ₂N⁻, (R _F CO) ₂CQ⁻, R _F COCQ₂⁻, QCOC (CN) ₂⁻, (R _F CO) ₂CSO₂R _F ⁻, (R _F CO) ₂CSO₂NR₂⁻, R- (OCH₂CH₂) _j -CH₂COC (CN) ₂⁻;
= sulfonamides such as QN (SO₂R _F ) ⁻;
Q representing CN, R, RCO, R₂NCO, R₂NCS, R _F , R _F CO or a heterocycle, R _F representing a perhaloalkyl or perhaloaryl radical, R representing an alkyl, oxaalkyl or aryl group.

Z and Y can also represent, simultaneously or not, a biradical or more generally a multiradical, for example - (R _F SO₂) NQ′N (SO₂R _F ) -, Q ′ representing a divalent radical having functionalities similar to those of Q and R _F having the meaning given above.

The polymers which can be used for the material of the present invention are those which comprise, on the polymer screen, solvation units which contain at least one heteroatom such as O, N, F, S.
Among these polymers, mention may be made of those for which the solvation unit of the polymer frame is an ether group or an amine group.
When the solvation units are ether groups, the polymeric frame can consist of a homopolymer, a block copolymer, a random copolymer, an alternating copolymer or a comb copolymer of ethylene oxide structure. When it is a homopolymer, the polymer frame advantageously consists of poly (ethylene oxide). Among the copolymers, mention may be made of a copolymer of ethylene oxide with a cyclic ether chosen from propylene oxide, methylglycidylether, allylglycidylether, dioxolane.
Another family of interesting polymers is constituted by those whose polymeric framework is constituted by a poly [alkoxy (oligoethyleneoxy) phosphazene], by a poly [alkoxyoligoethyleneoxy) siloxane] or by a poly [alkoxy (oligoethyleneoxy) vinyl ether].

The materials according to the invention are prepared by dissolving in a solvating polymer, a salt AY _p and a salt MZ _n , the respective proportions of the constituents of the mixture being such that the relation z + y - nx = p is satisfied and that they allow the coexistence in finite quantities of the complex anion [MZ _n Y _p ] ^p- and of a species chosen from the group consisting of the anion Z⁻, the anion Y⁻, the complex anion [MZ _n Y _{p + 1} ] ^{(p + 1) -} and the neutral species MZ _n .

The dissolution of the salt in the polymer can be carried out by dissolving the salts and the polymer in a common liquid solvent, then by evaporating the said solvent. Depending on the constituents used, either a film-forming plastic material or a viscous material is obtained.
The polymer can be crosslinked. If a pre-crosslinked polymer is used, the ionic compound is dissolved in a solvent, the pre-crosslinked polymer is impregnated with the solution obtained, then the solvent is removed. The polymer can also be crosslinked in situ. The crosslinking of the polymer frame can be carried out, for example by the action of a source of free radicals, ionizing radiation or an acid in the sense of Lewis. The polymer frame can also be crosslinked by polycondensation of a di- or tri-functional oligo (ethylene oxide), the ends of which are alcohol or amine functions, on an isocyanate of functionality at least equal to 2.

The dissolution of the salts can also be carried out by dry mixing the polymer and the salts in the form of powder, for example in a roller mill. Pressing the ground mixture allows the material to be obtained in the form of a film.

Various additives conventionally used for ionically conductive materials can be added to the mixture, to modify the properties of the final material. Thus, a plasticizing agent such as ethylene carbonate, propylene carbonate, γ-butyrolactone, dimethylformamide, N-methylpyrrolidone, tetraalkylsulfonamides, polyethylene glycols of mass between 200 and 2000 or their methyl ethers and, in general, derivatives of polar molecules of low volatility. The proportion of these additives can range from 1 to 90% of the total mass.

It is also possible to add one or more salts of an anion which cannot constitute a ligand of the cation M, for example to increase the conductivity of the material or to increase its amorphous nature. Among these salts, mention may be made of the salts AX, A having the meaning given above, X being a delocalized anion such as perchlorate, trifluoromethanesulfonate, bis trifluoromethanesulfonylimide.

Obtaining the material according to the invention in the form of a film is particularly advantageous for certain applications.

The materials of the present invention can be used for electrochemical generators. Such generators include a negative electrode "source" of the metal M at a high chemical potential, a positive electrode or "well" establishing a low chemical potential of M, the two electrodes being in contact via a polymer electrolyte consisting of a material according to the invention. Advantageously, at least one of the electrodes has a composite structure including the electrochemically active material, an electronic conductive material and the material according to the present invention.
The electronic conductive material can be graphite or a carbon black, particularly acetylene black.
The negative electrode preferably consists of metallic zinc, metallic magnesium, metallic lithium or one of its alloys, calcium or aluminum.

The materials of the present invention can also be used for an electrochemical system making it possible to act on the transmission of light. Such a system comprises a counter electrode, an electrolyte constituted by a material according to the invention and a transparent electrode. This electrode can serve as a substrate for the electrochemical deposition of M or as a support for an electrochromic layer. In such a system, the counter electrode is formed by a grid of metal M, possibly deposited on a transparent support. It can also be constituted by an electroactive material deposited on a transparent support, the electroactive material being chosen from those which do not undergo a color variation during the electrochemical reaction, or from those which have a color variation concomitant with that of the 'transparent electrode. The metal M is advantageously chosen from copper, zinc, nickel, tin, lead.

The materials of the present invention are described in more detail in the following examples, given by way of illustration, without limitation.

Example 1

792 mg of poly (ethylene oxide) PEO of mass 5.10⁶ g / mole, 166 mg of potassium iodide and 19 mg of copper iodide are dissolved with stirring in 30 ml of acetonitrile. The homogeneous solution obtained is poured into a glass ring 5 cm in diameter, placed on a PTFE plate. After evaporation of the solvent, an elastic yellow film about 25 μm thick is obtained. The variation of ionic conductivity of this material as a function of temperature is shown in Figure 1, during a rise in temperature (curve a) and during cooling (curve b).

Example 2

3.96 g of poly (ethylene oxide) PEO with a mass of 9.10⁵g / mole, 745 mg of potassium chloride and 1.09 g of zinc chloride are dissolved with stirring in 25 ml of methyl formate. The homogeneous solution obtained, which contains the complex anions ZnCl₃⁻ and ZnCl₄²⁻, is spread using a template on a polypropylene plate. After evaporation of the solvent, a transparent elastic film approximately 100 μm thick is obtained. The variation of the ionic conductivity of this material as a function of the temperature is shown in FIG. 2 during cooling (curve a) and during a rise in temperature (curve b).

Example 3

2.83 g of poly (methoxy-ethoxy-ethoxyphosphazene prepared according to the method described by: HR Allcock, PE Austin, TX Neenan, JT Sisko, PM Blonsky & DF Shriver, Macromolecules 19 , 1508 (1986), 382 mg of chloride of guanidinium and 272 mg of zinc chloride are dissolved with stirring in 20 ml of acetone. The homogeneous solution obtained is evaporated. A very viscous transparent material is obtained. The conductivity, measured at 22 ° C., is greater than 5.10⁻⁵ ( Ωcm) ⁻¹.

Example 4

2.1 g of polyethylene glycol 400-co-oxymethylene with mass ≅ 10⁵ g / mole were prepared according to the method described in: CV Nicholas, DJ Wilson, C. Booth & RJM Giles Brit. Polym. J. 20 289 (1988). 760 mg of potassium trifluoroacetate and 1.16 g of zinc trifluoroacetate are dissolved with stirring in 20 ml of acetonitrile. The homogeneous solution obtained, which contains the CF₃CO₂⁻ and [(CF₃CO₂) ₃Zn] ⁻ ions, is evaporated under the conditions of Example 1. A very sticky transparent film is obtained. The conductivity measured at 22 ° C is greater than 7.10⁻⁵ (Ωcm) ⁻¹.

Example 5

5.28 g of poly (ethylene oxide) PEO with mass 5.10⁶g / mole, 1.03 g of sodium bromide and 1.33 g of anhydrous aluminum bromide are dry mixed in a zirconia ball mill . The powder obtained is pressed at 80 ° C under 400 bars in a sealed mold. A semi-crystalline white film of approximately 50 μm in thickness is obtained which is stored in a glove box under dry atmosphere (<1vpm).

Example 6

4 g of poly (ethylene oxide) PEO-triol with a mass of 3080 g / mole from the firm Daiichi Kogyo Seiyaku Co, 372 mg of potassium chloride and 552 mg of anhydrous cobalt chloride are mixed with 4 ml of acetonitrile. After dissolution, 327 mg of hexamethylene diisocyanate and a drop of dibutyltin dilaurate (catalyst) are added. The blue solution obtained is poured into a mold formed by two polypropylene plates separated by 0.8 mm and with a seal on 3 sides. After 72 hours, the polymer network obtained by the polycondensation reaction is removed from the mold and the acetonitrile is evaporated in a stream of dry nitrogen. An elastic membrane is obtained which has very good mechanical properties and whose conductivity is, at 50 ° C, 3.10⁻⁵ (Ωcm) ⁻¹, in which the CoCl₃⁻ and CoCl₄²⁻ ions coexist.

Example 7

The cesium salt of bis (trifluoroacetyl) imide is prepared by reaction of (CF₃CO) ₂NH with an excess of cesium carbonate in acetonitrile. After evaporation, the salt is extracted with methyl formate and crystallized. To 5.11 g of the cesium salt dissolved in 20 ml of tetrahydrofuran, 423 mg of anhydrous lithium chloride are added; a precipitate of CsCl is formed which is separated by centrifugation. 10 ml of the supernatant solution are added to 6.6 g of a terpolymer of ethylene oxide (80%), methyl-glycidyl ether (15%) and allyl-glycidyl ether (5%) by mass M _w ≅ 2.5.10⁵ in solution in acetonitrile. To the solution is added 1% by weight relative to the benzoyl peroxide polymer. A film of polymer-salt complex, which contains a mixture of (CF₃CO) ₂N⁻ and of [(CF₃CO) ₂N₂Li] ⁻, is spread using a template to correspond to a thickness of 40 µm after evaporation of the solvent. The dry film is heated under a dry argon atmosphere at 80 ° C for 3 h. Cross-linking of the polymer chains takes place by the double bonds of the allyl group, initiated by the peroxide. The film obtained has excellent mechanical properties and its conductivity is 7.10⁻⁵ (Ωcm) ⁻¹ at 26 ° C.

Example 8

484 mg of poly (ethylene oxide) PEO mass 5.10⁶ g / mole, 246 mg of cesium trifluoroacetate and 71 mg of nickel trifluoroacetate are dissolved with stirring in 15 ml of acetonitrile. The formation of the Ni complex (CF₃CO₂) ₃⁻ is highlighted by its intense green coloring. The homogeneous solution obtained is poured into a glass ring 4 cm in diameter placed on a PTFE plate. After evaporation of the solvent, an elastic film approximately 25 μm thick is obtained.

Example 9

1.4 g of poly (methoxy-ethoxy-ethoxy) phosphazene prepared according to the method described by: HR Allcock, PE Austin, TX Neenan, JT Sisko ,, PM Blonsky & DF Shriver, Macromolecules 19 , 1508 (1986), 378 mg anhydrous tin chloride and 168 mg of cesium bromide are dissolved with stirring in 20 ml of methyl formate. The homogeneous solution obtained is evaporated. A very viscous transparent material is obtained which contains the anion SnCl₂Br⁻ and the neutral salt SnCl₂ solvated by the polymer.

The conductivity, measured at 22 ° C, is greater than 5.10⁻⁵ (Ωcm) ⁻¹.

Example 10

900 mg of copolymer of Example 7, 152 mg of potassium trifluoroacetate, 125 mg of magnesium trifluoroacetate and 20 mg of azobis (cyanovaleric acid) are dissolved in 10 ml of acetonitrile. Evaporation of the solution in a glass ring on PTFE and heating under argon at 80 ° C produce an elastic film with a conductivity of 5.10⁻⁴ (Ωcm) ⁻¹ at 55 ° C. In this material coexist the salts K⁺CF₃CO₂⁻ and K⁺ [(CF₃CO₂) ₃Mg] ⁻.

Example 11

440 mg of poly (ethylene oxide) PEO of mass 5.10⁶ g / mole, 660 mg of bis (trifluoroacetyl imide) of magnesium and 152 mg of cesium fluoride are dissolved with stirring in 15 ml of acetonitrile. This composition corresponds to the coexistence of the complexes {Mg [(CF₃CO) ₂N] ₂} ₂F⁻ and Mg [(CF₃CO) ₂N] ₂F⁻. The homogeneous solution obtained is poured into a glass ring with a diameter of 4 cm placed on a PTFE plate. After evaporation of the solvent, an elastic film approximately 25 μm thick is obtained.

Example 12

The compound CH₃OCH₂CH₂NH (SO₂CF₃) is prepared by reaction of trifluoromethane-sulfonyl imidazole on methoxyethylamine. The compound is distilled under reduced pressure after acidification with hydrochloric acid. To 1.2 g of this compound are added 2 ml of a 0.5M solution of magnesium methyl carbonate in methanol and 277 mg of potassium carbonate. The resulting solution is filtered and evaporated. 342 mg complex and 396 mg poly (ethylene oxide) mass M _w ≅ 5.10⁶ are dissolved in 20 ml of acetonitrile. The homogeneous mixture is poured into a glass ring placed on a polished PTFE plate. After evaporation, a 55 µm thick film is obtained, the conductivity of which at 60 ° C is 4.10⁻⁴ (Ωcm) ⁻¹.

Example 13

2-methoxytetrafluoropropionic acid is prepared according to the method described in J. Org. Chem 31 2312, (1966) from hexafluoropropene oxide. 5.25 g of this acid are treated with 3.5 g of potassium hydrogen carbonate in 10 ml of water. After reaction, the water is evaporated under reduced pressure and the solid residue is extracted with 20 ml of methyl formate. After evaporation of the organic solution, the salt K [CH₃OCF (CF₃) CO₂] is obtained. 4.26 g of this salt is dissolved in 15 nl of acetonitrile and 300 mg of anhydrous magnesium chloride are added. The KCl precipitate is removed by centrifugation and the supernatant solution is mixed with 15 g of poly (oxide ethylene) with a mass of 9.10 m g / mole in 200 ml of acetonitrile. The solution is degassed and poured onto a glass plate. After evaporation and drying, a 70 μm thick film is obtained, the conductivity of which at 80 ° C. is 2.10⁻³ (Ωcm) ⁻¹.

Example 14

est préparé en condensant le chlorure de trifluoroacétyle sur le sel de potassium de l'acide tétronique en présence de pyridine. A 2,24 g du sel de potassium de l'acide trifluoroacétyle tétrolique dans 20 ml d'acétonitrile sont ajoutés 105 mg de chlorure de lithium anhydre. Le précipité de chlorure de potassium est séparé, puis la solution surnageante est mélangée à 3,3 g de polyéthylène glycol 400-co-oxyméthylène de masse ≅ 10⁵ g/mole dans 30 ml de tétrahydrofurane. Le polymère a été préparé selon la méthode décrite dans : C.V. Nicholas, D.J. Wilson, C. Booth & R.J.M. Giles Brit. Polym. J. 20 289 (1988). La solution est dégazée et coulée sur une plaque de verre. Après évaporation et séchage, on obtient un film de 95 µm d'épaisseur dont la conductivité à 68°C est de 9.10⁻⁴ (Ωcm)⁻¹.Tetronic trifluoroacetyl acid:

is prepared by condensing trifluoroacetyl chloride on the potassium salt of tetronic acid in the presence of pyridine. To 2.24 g of the potassium salt of trifluoroacetyl tetrolic acid in 20 ml of acetonitrile are added 105 mg of anhydrous lithium chloride. The potassium chloride precipitate is separated, then the supernatant solution is mixed with 3.3 g of polyethylene glycol 400-co-oxymethylene with mass ≅ 10⁵ g / mole in 30 ml of tetrahydrofuran. The polymer was prepared according to the method described in: CV Nicholas, DJ Wilson, C. Booth & RJM Giles Brit. Polym. J. 20 289 (1988). The solution is degassed and poured onto a glass plate. After evaporation and drying, a film 95 μm thick is obtained, the conductivity of which at 68 ° C. is 9.10⁻⁴ (Ωcm) ⁻¹.

Example 15

The procedure of Example 14 was reproduced, replacing the trifluoroacetyl tetronic acid successively with each of the following acids:

The conductivity of the films obtained was greater than 10⁻⁴ (Ωcm) ⁻¹ at 70 ° C.

Example 16

The salt K⁺CH₃-OCH₂COC (CN) ₂⁻ is prepared by the action of methoxyacetyl chloride on the potassium derivative of malononitrile K⁺HC (CN) ₂ in pyridine, then treatment with potassium carbonate. To 1.76 g of this salt in 10 ml of acetonitrile are added 430 mg of anhydrous europium chloride. The KCl precipitate is removed by centrifugation and 2.2 g of ethylene oxide (80%) - methyl glycidyl ether (20%) copolymer are added. After evaporation, under the conditions of Example 1, a polymer electrolyte film containing the rare earth metal is obtained in the form of an anionic complex EuZ₃⁻ with Z = CH₃-OCH₂COC (CN) ₂.

Example 17

et 150 mg de noir d'acétylène. L'ensemble forme un film de 125 µm d'épaisseur sur un collecteur en polypropylène (12 µm) métallisé par une couche de molybdène d'environ 200 nm. L'ensemble est découpé au même diamètre. Les trois éléments sont pressés ensemble à 90°C sous 2.10⁵Pa. A 70°C, la f.e.m. de la batterie ainsi constituée est de 1,15 Volts et sa capacité sous 50 µA/cm² jusqu'à la tension de coupure de 0,8 V est de 8 C/cm². Ce générateur est rechargeable.A secondary electrochemical generator comprises a negative electrode constituted by a zinc sheet 20 μm thick, cut in the form of a disc 3 cm in diameter; an electrolyte consisting of the polymer material according to Example 2; a positive electrode having a composite structure obtained by evaporation of a suspension containing 580 mg of the material of the electrolyte, 965 mg of poly dimercaptothiadiazole of formula:

and 150 mg of acetylene black. The assembly forms a film of 125 μm thickness on a polypropylene collector (12 μm) metallized by a layer of molybdenum of approximately 200 nm. The whole is cut to the same diameter. The three elements are pressed together at 90 ° C at 2.10⁵Pa. At 70 ° C, the fem of the battery thus formed is 1.15 Volts and its capacity under 50 µA / cm² until the cut-off voltage of 0.8 V is 8 C / cm². This generator is rechargeable.

Example 18

A secondary generator is manufactured with the following electrochemical chain:

The electrolyte is that described in Example 11. The composition of the positive electrode corresponds to 42% v / v of electrolyte, 8% v / v of acetylene black and 50% v / v of graphite fluoride CF _x (x ≅ 1). The composite material diluted in acetonitrile is spread on an 8 µm copper foil so as to form a layer about 80 µm thick. The negative electrode is a 20 µm sheet. The battery voltage after assembly by rolling the cells at 80 ° C is 2.5 V and the capacity for a flow rate of 300 µA / cm² is 7 mAh / cm².

Example 19

An electrochemical generator comprises a negative electrode consisting of a 25 μm thick lithium sheet, an electrolyte prepared according to example 7 and a composite electrode whose active material is vanadium oxide V₂O₅ (55 % v / v), acetylene black (6% v / v) and the same electrolyte. The thickness of the positive electrode is 45 µm. The capacity is 8 Coulombs / cm² for a cut-off voltage of 2.2 Volts.

Example 20

A variable transmission glazing device is constructed as follows: on a glass plate covered with a layer of doped indium oxide (ITO) so as to obtain a resistance of 10 Ω square, a layer of the polymer electrolyte described in Example 1. The counter electrode is formed by a deposit of 1 μm of metallic copper on another glass plate of similar size. The continuous layer is transformed by photogravure into a grid with square meshes of 15 µm side and thickness 2 µm. The assembly takes place under vacuum at 80 ° C with the application of a mechanical force of 4.9.10⁵ Pa (5 kg / cm²). By applying a voltage of 1 Volt between the metal grid and the ITO layer (pole), we observe the appearance of a reflective deposit of copper. By reversal of polarities, the transparency of the system is restored in a few seconds.

Example 21

A flexible device with electrically controlled optical transmission is constructed in the following manner: on a film of poly (ethylene terephthalate) (PET) covered by cathodic sputtering with a layer of tin oxide doped with fluorine (SnO₂ / F) of so as to obtain a resistance of 50 Ω square, a layer of the polymer electrolyte described in example 9 is deposited. The counter electrode is formed by a deposit of 1 μm of metallic tin on a film of PET. The continuous layer is transformed by photogravure into a grid with square meshes of 15 µm side and thickness 2 µm. The assembly takes place under vacuum at 80 ° C by rolling the elements. By applying a voltage of 0.8 Volt between the metal grid and the ITO layer (pole-), the appearance of a reflective tin deposit is observed. By reversing the polarities, the transparency of the system is restored in ≅ 1 minute.

Claims (21)

1. Ionically conductive material comprising a solid solution of one or more salts in a polymer, characterized in that the transport and the mobility of a metal cation Mⁿ⁺ which has the valency n are provided by at least one complex anion corresponding to the general formula [MZ_nY_p]^p-, formed between an anionic ligand Z⁻, an anionic ligand Y⁻ and the cation Mⁿ⁺, with 1 ≦ n ≦ 5 and 1 ≦ p ≦ 3.
2. Material according to claim 1, characterized in that the solid solution is a polymeric complex denoted by the overall formula $${\text{Poly(s.u.)}}_{\text{u}}{\text{A(M}}_{\text{x}}{\text{Z}}_{\text{z}}{\text{Y}}_{\text{y}}\text{)}$$

   

   in which

   - A is a cation of valency p capable of being easily solvated by the polymer, with p = 1 or 2;

   - (s.u.) denotes the solvation unit of the polymer;

   - u denotes the number of solvation units carried by the macromolecular framework which are needed for solvating a cation A;

   - x, y and z are such that the relationship z + y - nx = p is satisfied and that they permit the coexistence, in finite quantities, of the complex anion [MZ_nY_p]^p- and of a species chosen from the group consisting of the anion Z⁻, the anion Y⁻, the complex anion [MZ_nY_p+1]^(p+1)- , the complex anion [MZ_n+1Y_p]^(p+1)- and the neutral species MZ_n.
3. Material according to claim 2, characterized in that the cation A is chosen from alkali metals, alkaline-earth metals, quaternary ammonium radicals corresponding to the formula NH_(4-j)R_j⁺, amidinium radicals corresponding to the formula RC(NH_2-jR_j)₂⁺, guanidinium radicals corresponding to the formula C(NH_2-jR_j)₃⁺, with j = 0, 1 or 2, R being chosen from hydrogen and an alkyl, oxaalkyl or aryl group.
4. Material according to any one of claims 1 to 3, characterized in that the cation Mⁿ⁺ is a cation derived from an element chosen from Li, Mg, Ca, Sr, Mn, Fe, Ni, Co, Cu(I), Cu(II), Ag, Zn, Cd, Al, Sn(II), Sn(IV), Bi, Hg, Pb, Y and the rare earths.
5. Material according to any one of claims 1 to 4, characterized in that Z⁻ and Y⁻, which are identical or different, are chosen from:
      = halogens such as F⁻, Cl⁻, Br⁻, I⁻;
      = pseudohalogens corresponding to the formula QS⁻;
      = the radicals R_FCO₂⁻, (R_FCO)₂N⁻, (R_FCO)₂CQ⁻, R_FCOCQ₂⁻, QCOC(CN)₂⁻, (R_FCO)₂CSO₂R_F⁻, (R_FCO)₂CSO₂NR₂⁻, R-(OCH₂CH₂)_j-CH₂COC(CN)₂⁻;
      = sulfonamides QN(SO₂R_F)⁻;
   Q denoting CN, R, RCO, R₂NCO, R₂NCS, R_F, R_FCO or a heterocyclic ring, R_F denoting a perhaloalkyl or perhaloaryl radical, R denoting an alkyl, oxaalkyl or aryl radical.
6. Material according to any one of claims 1 to 4, characterized in that Z and Y denote a multiradical, simultaneously or otherwise.
7. Material according to claim 6, characterized in that the multiradical is a biradical denoted by the formula -(R_FSO₂)NQ′N(SO₂R_F)⁻, in which Q′ denotes a bivalent radical carrying at least one functional group chosen from CN, R, RCO, R₂NCO, R₂NCS, R_F, R_FCO or a heterocyclic ring, R_F denoting a perhaloalkyl or perhaloaryl radical, R denoting an alkyl, oxaalkyl or aryl radical.
8. Material according to any one of claims 1 to 7, characterized in that the solvation unit of the polymeric framework contains at least one heteroatom chosen from 0, N, F and S.
9. Material according to claim 8, characterized in that the solvation unit of the polymeric framework is an ether group or an amine group.
10. Material according to claim 9, characterized in that the polymeric framework consists of a homopolymer, a block copolymer, a random copolymer, an alternating copolymer or an ethylene oxide copolymer with a comb structure.
11. Material according to any one of claims 1 to 10, characterized in that it contains additives chosen from salts of anions which cannot form a ligand for the ion Mⁿ⁺ and from plasticizing agents.
12. Process for the preparation of a material according to any one of claims 1 to 11, characterized in that a salt AY_p and a salt MZ_n are dissolved in a solvating polymer, in proportions such that the relationship z + y - nx = p is satisfied and that they permit the coexistence, in finite quantities, of the complex anion [MZ_nY_p]^p- and of a species chosen from the group consisting of the anion Z⁻, the anion Y⁻, the complex anion [MZ_nY_p+1]^(p+1)- and the neutral species MZ_n.
13. Process according to claim 12, characterized in that the salts and the polymer are dissolved in a common liquid solvent which is then evaporated.
14. Process according to claim 13, characterized in that the polymer is crosslinked in situ.
15. Process according to claim 12, characterized in that the polymer is precrosslinked and impregnated with a solution of salt in an organic solvent, this solvent being removed after the impregnation.
16. Process according to claim 12, characterized in that the salts are dissolved in the polymer in dry state by grinding.
17. Electrochemical generator, characterized in that it comprises as electrolyte a material according to any one of claims 1 to 11.
18. Generator according to claim 17, characterized in that it comprises a negative electrode which is a source of metal M with a high chemical potential, a positive electrode or "well" establishing a low chemical potential of M, the two electrodes being in contact through the intermediacy of the electrolyte.
19. Electrochemical generator according to either of claims 17 and 18, characterized in that at least one of the electrodes has a composite structure including an electrochemically active material, an electronically conductive material and the material forming the electrolyte.
20. Electrochemical system which makes it possible to affect the transmission of light, comprising a counterelectrode, an electrolyte, and a transparent electrode used as substrate for the electrochemical deposition of the metal M, characterized in that the electrolyte is a material according to any one of claims 1 to 11.
21. Electrochemical system according to claim 20, characterized in that the counterelectrode consists of a grid of the metal M, optionally deposited on a transparent support.

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